1. What you want to do is visit the following site and download Qonverge. As far as I can remember, it has compiling tools, a wad converter and the fgd. I use this myself.

http://www.icculus.org/homepages/riot/

2. Yes, there's one big disadvantage. Quoting from Riot's site, There is some legal garbage surrounding this. You see, you're legally allowed to make Quake maps with Worldcraft 3, but not Hammer. <snip> I am also allowed to tell you that the Worldcraft 3's files are totally compatible with Hammer's and that you couldn't tell the difference between a map made in Hammer or Worldcraft even if you had the source files. I assure you, however, that this whole thing is entirely coincidental.

4. I edit the wads while they're still in Quake format using TexMex, then convert them over to Half-Life. See link above for a Quake -> HL wad converter.

5. Any fgd should work just fine. I have been using the Chapters fgd a bit, and have had no problems yet. 

It's the one thing that really sucks ass about it and I'm thinking of changing over to hammer for any future maps I might make for Quake.

Having said that, I did fire off an email to Valve's Yahn Bernier the other day about WC 1.6a full. I asked if they would consider making it abandonware so we can distribute it freely. I got a quick (short but also it came within 5 mins of me sending the original email) reply saying he as forwarded it to couple of people who might be able to help, which was very promising - however, I can't check my email because I'm on holiday now and I sent it via my work email address. DOH! 

Thanks for that information.

I'm looking to do things proper, are there any major differences between Worldcraft 3 vs. Value Hammer?

Does Worldcraft 3 have the ability to rotate things without messing up the textures? Are there any major differences between 3.0 and 3.4 from the perspective of Quake maps. (I'm assuming it's just a name change/license agreement change)

Also, Hammer seems to be free (as far as I can tell). So far, it looks like Worldcraft 3.0 uses the shareware vs. full system of things.

"It's the one thing that really sucks ass about it and I'm thinking of changing over to hammer for any future maps I might make for Quake."

Yeah, it's the ONLY thing I don't like about Worldcraft 1.6a, otherwise it is totally awesome in my experience (maybe there is something GTKRadiant or Quark or maybe even BSP can do better, but my limited imagination can see what it would be.) 

I did fire off an email to Valve's Yahn Bernier the other day about WC 1.6a full. I asked if they would consider making it abandonware so we can distribute it freely.

I just checked and the Worldcraft 3.3 is the first version with texture rotation.

How can I tell if making Quake maps is permitted with it? The page referenced in the first reply says Worldcraft 3 can be used to make Quake maps, so I'm guess that Worldcraft (any version) can be used for Quake but Hammer (any version) can't be.

So if 3.3 has the texture rotation fix, from a pure Quake perspective I don't think there is a difference.

Maybe if you check your email you might ask the Value people if they might allow Quake maps to be made with it in a 100% unsupported way so they have no obligation to support that use of it. 

Worldcraft 3.3 Download link:

http://www.fileplanet.com/44990/download/WorldCraft-v3.3

4) What's New in Version 3.3

* OpenGL 3D Renderer. The real-time renderer is much faster, more robust, and allows for animating visuals in the 3D view.

* Texture Locking. Texture alignment is now preserved through rotation, scaling, and flipping, allowing for the hassle-free construction of odd-angled geometry.

* Powerful Texture Application Features. Automatic texture continuity is guaranteed when lifting and applying from one face to another. Textures can be fit across one face or multiple faces, or aligned to the left, right, top, bottom, and center of faces with a single button click. Textures can be projected onto faces from an arbitrary viewpoint, useful for texturing cliff faces or other irregular geometry. In addition, texture axes are now displayed in the 3D view.  

How can I tell if making Quake maps is permitted with it? The page referenced in the first reply says Worldcraft 3 can be used to make Quake maps, so I'm guess that Worldcraft (any version) can be used for Quake but Hammer (any version) can't be.

That's pretty much it right there. The, ehh, EULA was changed when they renamed WorldCraft to Hammer (version 3.4), so you can't legally make Quake maps with it. The differences between 3.3 and 3.4 are absolutely minimal. 

That's the only reason I needed for me to make all my Quake maps with Hammer. I can't remember what I had to do to set it up for Quake, but I followed a guide on teh internet, so Google is your friend here. God knows how I would have made Marcher in an editor without some kind of layer functionality or way of logically grouping areas o_O 

Here are some pictures showing my hammer setup.

http://republika.pl/quake_1/hammer2.png
http://republika.pl/quake_1/hammer3.png
http://republika.pl/quake_1/hammer4.png
http://republika.pl/quake_1/hammer5.png
http://republika.pl/quake_1/hammer6.png
http://republika.pl/quake_1/hammer7.png
http://republika.pl/quake_1/compile.txt
http://republika.pl/quake_1/hammer1.png


I have the compiling tools in the rmf directory together with my bat files for running the tools. Running the compilation from hammer is fast and easy but sometimes I'm using the bat files if the compile time is longer.
You have to change the wad files to wad3 format (in Texmex) if you want to use them with hammer.
Hammer has some slight advantages over worldcraft 1.6a but I don't remeber them anymore . It has also some annoying bugs.
Woldcraft 1.6 has the vis grop functionality if i remember it right.